1. Field of the Invention
The present invention relates to a semiconductor device, and, more specifically, to a light-emitting device having a light-emitting element formed on a substrate with an insulated surface and a method of manufacturing the same. The invention also relates to an organic light-emitting module having an IC or the like including a controller mounted on an organic light-emitting panel. In this specification, both the organic light-emitting panel and the organic light-emitting module are referred to as a light-emitting device.
2. Description of the Related Art
In recent years, research on a light-emitting device having a light-emitting element as a self-luminous element has been accelerated, and specifically, a light-emitting device employing organic material as EL material attracts people's attention. This light-emitting device is also referred to as EL display or light-emitting diode.
The light-emitting element includes a layer containing an organic compound that provides an electro luminescence generated by being applied with an electric field (hereinafter referred to as EL layer), an anode, and a cathode. The luminescence of the organic compound includes light emission (fluorescent radiation) generated when restoring from a singlet excitation state to the normal state and light emission (phosphorescence) when restoring from a triplet excitation state to the normal state. The light-emitting device manufactured by a film forming device and a method of forming a film according to the invention may be applied to both of the cases employing these light-emissions.
The light-emitting device is characterized by having no limitation in angle of visibility because it is a self-luminous type, which is different from the liquid crystal display unit. In other words, it is superior to the liquid crystal display as a display to be used in the open air, and usages in various ways have been proposed.
The light-emitting element has such a structure that the EL layer is interposed between a pair of electrodes, and the EL layer generally has a laminated structure. Typically, such a laminated structure as “hole transport layer/light emitting layer/electron transport layer” is employed. This structure has very high light-emitting efficiency, and most of the light-emitting devices that are currently under research and development employ this structure.
The structure laminating in order of “hole injection layer/hole transport layer/light emitting layer/electron transport layer, or hole injection layer/hole transport layer/light emitting layer/electron transport layer/electron injection layer may also be employed on the anode. It is also possible to dope the fluorescent coloring matter to the light-emitting layer. These layers may be formed only from low molecular material or only from high molecular material.
In this specification, all the layers provided between the cathode and the anode are referred to as EL layer as a generic name. Therefore, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, and electron injection layer are all included in the EL layer.
In this specification, the light-emitting diode constructed of the cathode, the EL layer, and the anode is referred to as a light-emitting element, which includes a system in which the EL layer is formed between two kinds of striped electrodes arranged so as to be orthogonal with each other (simple matrix system) and a system in which the EL layer is formed between the pixel electrode and the opposite electrode connected to the TFT (Thin Film Transistor) and arranged in matrix (active matrix system).
The EL material forming the EL layer is generally divided into the low molecular (monomeric) material and the high molecular (polymeric) material. In the case of the low molecular material, the film is formed mainly by vapor deposition.
Publicly known representative vapor deposition includes resistive heating in which resistive heaters are disposed around a container containing deposition material therein to heat it indirectly by energizing the resistive heaters so that the deposition material is heated and evaporated, and electron gun deposition (also referred to as EB vapor deposition) in which a beam of electron is irradiated on the deposition material to allow it to evaporate. A method in which a container formed of metal (containing an deposition material therein) is directly energized and heated to allow the deposition material contained therein to evaporate, and a method in which a container formed of a light transmittance material such as quartz (containing an deposition material therein) is radiated and heated by an infrared ray lamp to allow the material contained therein to evaporate.
Since the deposition material formed of an organic compound is resolved when irradiated by a beam of electron because energy of a beam of electron is too high, other types of vapor deposition are employed in many cases. In contrast to it, electron gun deposition is generally employed for depositing a metallic thin film, which is an inorganic material whereof the fusing point is relatively high as a cathode or an anode of the light-emitting diode, because it can easily stabilize the film formation rate.